One of the fields of the art that has been subjected to more intensive development is the field of EGR systems for thermal combustion engines since recirculating exhaust gas requires solving many technical problems given the demands of handling a high temperature gas that contains corrosive products, may generate condensates, and furthermore also contains particles that may damage sensitive parts of the engine.
In this scenario, each of the functions necessary in an EGR system is handled by a component dedicated to solve said function. The increase in components suitable for solving particular technical problems and of additional functions in EGR gas management has larger space requirements and since the engine bay in a vehicle is limited, the solutions used today seek higher degrees of packing or compactness.
This higher degree of packing is obtained by searching for cavities and gaps where the different devices can be arranged, adapting their shape to adjust them to said cavities without being considerably detrimental to operation. These devices are communicated with pipes establishing fluid connection (for example of the EGR gas or a coolant) with the point of the circuit where an inlet or outlet must be incorporated in a certain circuit or system.
One of the examples of the devices requiring packing solutions is the heat exchanger of an EGR system (known as EGR cooler). Once located in the suitable place with an orientation also suitable to comply with packing and operating requirements, the EGR heat exchanger requires inlet pipes from the exhaust pipe and outlet pipes for the cooled gas heading towards the intake of the internal combustion engine with the interposition of an EGR valve for managing the recirculated gas flow rate or for managing the gas heading towards the exhaust.
The low-pressure systems are those in which the EGR system is on the low-pressure side with respect to the turbo-compressor unit.
Particularly, low-pressure EGR systems use a catalytic converter, a particle filter primarily for catching cinder or both. In addition to these filters, there are other filters typically referred to as emergency filters that prevent very hard solid particles, such as ceramic particles, for example, that have detached from previous filters, from reaching the compressor. The compressor blades are particularly sensitive and the introduction of solid particles causes serious damage to this device. Throughout the text, when only particle filter or antiparticle filter or catalytic converter is indicated, it refers to the former unless otherwise explicitly indicated.
The most commonly used solutions in the state of the art require pipes establishing a connection between the particle filter outlet or the catalytic converter outlet and the EGR heat exchanger inlet, and also between the EGR heat exchanger outlet with the intake of the engine, usually with the interposition of the EGR valve.
Although this configuration allows a certain degree of packing, the use of pipes which also take up space is still required.
The present invention solves the problem of the use of pipes and of obtaining a higher degree of packing by integrating the EGR heat exchanger with the catalytic converter or with the particle filter, establishing a particular structure of the heat exchanger such that it adapts to the large outlet diameter of either the catalytic converter or the particle filter. The configuration of the exchanger, which is adapted to be integrated in the catalytic converter or in the particle filter, additionally incorporates a valve particularly configured so that the heat exchanger of the EGR system can be used to recover heat from the exhaust pipe when the EGR gas does not need to be cooled.
The modular configuration, defining a first module for the catalytic converter, the particle filter or both, and a second module for the heat recovery unit, facilitates the independent manufacture of both and its easy replacement. Likewise, the configuration of both with a screwed attachment according to the special manner of being attached to one another assures a secure and quick attachment.
The device of the invention is of particular interest as it also pertains to technical solutions leading to environmentally friendly vehicle engines.